27 GARDEN LEVEL EXHIBITS of those ancient plants This specimen w as found abo ve a coal layer in an abandoned strip mine in P ennsylvania It contains the remains of seed ferns Neuropteris o vata and Alethopteris serlii Sphaler it e This slab from the Commodore No 5 mine in Creede Colorado shows hun dreds of near perfect sphalerite crystals Sphalerite is a heavy mineral that of ten forms brilliantly shin y crystals but also occur s as dull fnegrained masses This crystal slab formed one w all of a vein where ore minerals were deposited from hot w ater s containing dissolved zinc lead and copper This specimen also contains small amounts of dark gray g alena and brassy c hal copyrite Sphalerite gets its name from Greek sphaleros treac herous be cause its man y color s and growth habits mak e it diffcult to recogniz e and because it is easily confused with other minerals suc h as g alena and siderite Gift from the Geolog y Museum Colorado School of Mines Golden Colorado Chalcocit e Azur it e and Malac hit e This specimen two pieces is from the K ennecot t Compan y s J umbo mine one of the largest c halcociteric h ore bodies on record near McCar th y Alask a Chalcocite is the blac k mineral azurite is the deep blue or deep violet mineral and malac hite is the bright green one all are impor tant ores of copper Chal cocite is named from the Greek c halkos copper Gift from Edw ard M MacK e v ett Jr US Geological Surv e y Menlo P ark California Sand Calcit e Crystals S and calcite crystals lik e these occur in enormous quantities in a single bed of sand near Badlands National P ark This specimen is from R at tlesnak e But te south of Interior W ashabaugh County S outh Dakota Gift from the Department of Earth Sciences Univ ersity of South Dak ota V er million through V alentine J Ansfeld J adeit e J adeite boulder s of this siz e and c haracter were common on the banks and in the stream bed of Clear Creek S an Benito County California prior to the mid 1 950s Because of the tremendous interest shown by amateur mineralogists and roc khounds for jadeite and other lapidary materials the cour se of Clear Creek for several miles downstream and upstream from the Clear Creek mer cury mine w as within a few year s following the disco very of jadeite stripped bare of all jadeite boulder s J adeite is one of two minerals that constitute jade the gem material Al though tons of jadeite have been pic k ed up along the cour se of Clear Creek in S an Benito County very lit tle if an y of it can be considered true gemquality jade J ade is valued most highly when it is translucent or semitransparent intensely and evenly colored and without faws It gets its name from the Spanish piedra de ijada stone of the side because it w as applied to the side of the body to treat kidney disorder s Collected b y Charles W Chester man and donated b y him on behalf of the Department of Geolog y California Academ y of Sciences San F rancisco Leaf Impr ession When this fnely laminated roc k split it revealed the dual impression of a carboniz ed leaf The leaf fell into shallow lak e w ater where it w as gradually co vered by layer s of lim y mud and silt that were later compressed and ce mented to form roc k Purchased b y the Society After youve fnished viewing the specimens in these cases you can take the stairs back up to the frst foor